The present invention relates in general to control devices, and in particular to a control device for use with a cylinder lock having a cylindrical case or housing and a cylindrical plug arranged in the housing and being angularly adjustable relative to the latter. The cylindrical plug has a key channel extending along its center axis for receiving a magnetically coded key. The key activates a plurality of cylindrical control members arranged for rotation about their axis along the key channel. The cylindrical plug is connected to a conventional lock bolt.